Implants that involve magnets such as magnetic sphincters, stoma plugs, dental implants, etc., can be demagnetized by the MRI device. They should be removed prior to the examination.

A particular danger is presented by small metallic surgical implants. Haemostatic or other clips in the CNS can move in their position. Dislocation by magnetic attraction or torque presents a risk in MRI examinations. There is a minimal risk in other parts of the body, because after the healing phase of six to eight weeks, fibrosis and encasement of the clip help to keep it in a stable position.
The label stainless steel is not a guarantee for non-ferromagnetic steel.

See also Cardiac Pacemaker and MRI Safety.

With an open configuration MRI system neurosurgical procedures can be performed using image guidance. Open MRI can be used to guide interventional treatments or procedures, such as a biopsy.
Intraoperative MRI allows lesions to be precisely localized and targeted. Constantly updated images, correlated with images obtained pre-operatively, help to eliminate errors that can arise during framed and frameless stereotactic surgery when anatomic structures alter their position due to shifting or displacement of, e.g. brain parenchyma.
Intraoperative MRI can help with the identification of normal structures, such as blood vessels and is helpful in optimizing surgical approaches, achieving complete resection of intracerebral lesions, determining tumor margins and monitoring potential intraoperative complications.

Intravenous contrast agents used in MRI are distributed in the extracellular spaces of the body before being excreted. In this sense they are similar to iodinated X-ray contrast media. However, contrast agents used for MRI are quite different from conventional radiographic contrast media in structure and function and there is no known cross sensitivity between these types of contrast agents. Common MRI contrast agents use metal ions (e.g., gadolinium or manganese) complexed with organic molecules.
Gd-DTPA, an ionic linear molecule complex (gadopentetate dimeglumine) was the first marketed MRI contrast agent. Although the osmolality of this substances can be relatively high (up to 1940 mOsm/kg H2O) compared with plasma, adverse reactions and side effects are very rare. The used doses are smaller compared with radiographic contrast media.

See also Nonionic Intravenous Contrast Agents, Dotarem®, and Magnevist®.

The owner of MRI equipment has to ensure that the equipment does fulfill the local requirements.
In some countries, the requirements are more stringent than in others; in other countries, they are nonexistent.
The user in general is unable to check power output, gradient strength, or even field strength. The manufacturer has to cover authorized hardware and software updates after the initial installation and has to give guarantee for the requirements. Specially designed computer programs usually supervise the power output of MRI devices and will not allow or will interrupt any imaging or spectroscopy procedure exceeding those limits considered safe.

See also European Medicines Agency, FDA information:
www.fda.gov/cdrh/safety/mrisafety.html

From Siemens Medical Systems;
The MAGNETOM 7T is designed as an open research platform. 7T MRI provides anatomical detail at the submillimiter scale, enhanced contrast mechanisms, outstanding spectroscopy performance, ultra-high resolution functional imaging (fMRI), multinuclear whole-body MRI and functional information.
This ultra high field (UHF) MRI device is a research system and not cleared, approved or licensed in any jurisdiction for patient examinations.